RE: Are subroutines codependent?

I agree. We prefix our global variables with a 'g' to indicate they are global.

Kurt Anderson
Sr. Programmer/Analyst – Application Development, Service Delivery Platform

-----Original Message-----
From: RPG400-L [mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Vernon Hamberg
Sent: Tuesday, July 08, 2014 9:58 AM
To: RPG programming on the IBM i (AS/400 and iSeries)
Subject: Re: Are subroutines codependent?

If I may expand on this - I think that global variables are useful for things that are used everywhere. An alternative is to pass them as parameters to every procedure - this can get a bit cumbersome - so one makes one's choice.

The challenge with globals as I see it is to be sure that there are no side effects - that once set, they are pretty static. Or at least very carefully managed - that has always been a challenge with subroutines.

Now for a utility procedure - with a specific purpose - everything could and perhaps should be done using parameters and local variables and maybe a return value.

JMHO
Vern

On 7/8/2014 8:48 AM, Henrik Rützou wrote:

Buck

this is very easy - take middleware service programs as CGIDEV2,
HTTPAPI or powerEXT. They all have a lot of subprocedures that shares
global variables within the service program and general storage
allocations otherwise they could not run.


On Tue, Jul 8, 2014 at 3:22 PM, Buck Calabro <kc2hiz@xxxxxxxxx> wrote:

On 7/8/2014 4:46 AM, D*B wrote:

Additinal note:
global data and coupling procedures by global data is not bad design!
Bad design is to define data global, which is needed only local!!!

Hi Dieter,
This surprises me, which means I probably do not understand what you
mean. Could you please give an example of good design that couples
subprocedures with global variables?
--buck
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